Answer :
Final answer:
A Boutonniere deformity occurs when there is a rupture of a digit's central tendinous slip of the extensor hood, causing a distinct flexed position of the proximal interphalangeal joint and extended distal interphalangeal joint.
Explanation:
The hand deformity resulting from a rupture of a digit's central tendinous slip of the extensor hood is known as a Boutonniere deformity. In this condition, the central slip of the extensor tendon that extends the middle phalanx is disrupted, leading to the characteristic flexion of the proximal interphalangeal joint and extension of the distal interphalangeal joint. As a consequence, the lateral bands of the tendon slip to the side and cause the distal joint to extend, while the lack of tension in the central portion causes the proximal joint to stay flexed.
